Some wellbore devices are actuated at selected times, when they are downhole. They are actuated to perform a function such as setting, sealing, opening and closing. While the actuation of the wellbore device may be critical for proper wellbore operations, the devices are often deep in the ground and their condition cannot be readily ascertained.
One example wellbore device includes a hydraulic piston for example, such as a sliding sleeve mechanism. Wellbore fluid treatments may be conveyed through tubing strings that have one or more sliding sleeve mechanisms to control the setting operation of packers and/or to control the open/closed conditions of fluid treatment ports. If a sliding sleeve mechanism fails to be properly actuated, the wellbore process can be jeopardized. Sometimes, a ball or plug is dropped downhole to interact with or perhaps actuate wellbore devices. Information on the movement and location of the ball or plug may be useful in some wellbore operations.
In some operations, pressure monitoring is used to monitor hydraulic actuations. However, pressure monitoring is not always accurate.